Nearly half a century after the Equal Pay Act of 1963 was passed, women on average still earn less than men.

Washington, D.C. - infoZine - Scripps Howard Foundation Wire - According to Sen. Barbara Mikulski, D-Md., women earn 77 cents for every dollar men earn. While the exact figure is debatable Democrats and the Obama administration are pushing for a bill to make it easier for women to fight pay discrimination.

As expected, however, the Senate on Tuesday rejected the bill on a 52-47 vote on a motion to invoke cloture. Democrats needed 60 votes to open debate on the bill. Now, the bill is likely to die.

The Senate resumed debate Monday on the cloture motion for the Paycheck Fairness Act. The bill, sponsored by Mikulski, would strengthen the Equal Pay Act by increasing enforcement of equal pay laws.

"There is a lot of work to be done to ensure American women earn comparable pay for a day's work," Senate Majority Leader Harry Reid, D-Nev., said Monday on the Senate floor. "Women get an unfair shake in modern-day America, and we're in modern-day America. We're trying to do something about it."

The bill was considered likely to fail, with few Republicans expected to vote for it, just as it failed in 2010, with only 58 votes, not enough to overcome a filibuster.

Senate Minority Leader Mitch McConnell, R-Ky., declined comment.

But business groups were vocal in their opposition.

"The Paycheck Fairness Act would impose unprecedented government control over how employees are paid at even the nation's smallest employers," said a letter signed by the U.S. Chamber of Commerce, the National Federation of Independent Business and 21 other small business organizations. "This flawed legislation could outlaw many legitimate practices that employers currently use to set employee rates, even when there is no evidence of intentional discrimination."

The letter said the law already prohibits discrimination, including the Lilly Ledbetter Fair Pay Act of 2009, the first bill President Barack Obama signed after taking office. Another law would disturb the balance between employers and employees, the letter said.

In a conference call Monday, Obama urged Congress to pass the bill.

"If Congress passes the Paycheck Fairness Act, women are going to have access to more tools to claim equal pay for equal work," Obama said "If they don't, if Congress doesn't act, then women are still going to have difficulty enforcing and pressing for this basic principle."

The bill would close loopholes for employer defenses and prohibit employers from retaliating against employees who discuss their wages with other employees.

The bill would also allow civil suits against employers for sex discrimination. It would make it easier to create class action lawsuits in discrimination cases.

The part of the legislation that allows unlimited damages, even if pay discrepancy was unintentional, worries small business owners.

"The tough thing to do is to judge what is a comparable job, and that's tough to do with a blanket law," Susan Eckerly, chief lobbyist for the NFIB, said. "We have a problem with the unlimited damages. One lawsuit can put a small company out of business, and we just can't support that."

Mikulski and Obama have said the pay differential is 77 cents to the dollar. Others argue that it is less, and the number depends on what government data is used. Mikulski's figure is based on annual wages, which may not take into consideration the number of hours worked, pension plans or bonuses.

The bill would amend the Civil Rights Act of 1964 to require the Equal Employment Opportunity Commission to collect employers' pay information data regarding sex, race and national origin of employees for use in the enforcement of federal laws prohibiting pay discrimination.

"Women are the breadwinners for a lot of families, and if they're making less than men do for the same work, families are going to have to get by for less money for child care, tuition and rent. Small businesses [would] have fewer customers," Obama said. "Everybody suffers."

Reid expressed his concern about Republican opposition to the bill.

"It appears Republicans will wind up on the wrong side of this issue as well, sending the message to little girls across the country that their work is less valuable because they happen to be born female," Reid said.

Eckerly said discrimination is less likely in small businesses because of a family atmosphere.

"We trust our members to pay our employees fairly," she said.

Obama said it is up to the people to hold their senators accountable for their votes.

"Congress is not going to act because I said it's important," Obama said. "They're going to act because you guys are making your voices heard. So senators have to know you're holding them accountable. Everything that they're going to be hearing over the next 24 hours can make a difference in terms of how they vote."